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地震波在实际介质中的传播机制与其在理想弹性介质中不同,此时其携带的机械能被部分存储、部分耗损,使得地震波发生频散现象,在近地表疏松介质中这种吸收效应更为强烈,造成大沙漠区地震勘探得到的资料分辨率降低。为了有效提高地震资料的分辨率,对疏松介质的吸收效应进行合理补偿势在必行。但其能量补偿因子是一与频率有关的幂函数,随着地震波传播距离增大和频率提高而急剧加大,计算过程不稳定,进而产生大量人为假象。通过数值模拟研究了计算不稳定性的形成机制,在前人研究基础上,提出了保持计算稳定性条件。数值模拟和实际资料处理结果表明,在保持数值计算过程稳定、高频信号不发生畸变的前提下,应用相位移法可以最大限度地恢复被地层吸收、衰减的有效高频信号,合理地提高了地震资料的垂向分辨率。
The propagation mechanism of seismic waves in the actual medium is different from that in the ideal elastic medium. At this time, the mechanical energy carried by the seismic waves is partially stored and partially depleted, making the seismic waves disperse. This absorption effect is more intense in near-surface loose media, As a result, the resolution of data obtained by seismic exploration in the Great Desert is reduced. In order to effectively improve the resolution of seismic data, it is imperative to compensate the absorption effect of loose media reasonably. However, its energy compensation factor is a frequency-dependent power function. As seismic wave propagation distance increases and frequency increases sharply, the calculation process is not stable, resulting in a large number of artificial artifacts. The formation mechanism of calculation instability was studied by numerical simulation. On the basis of previous studies, the conditions for maintaining the stability of calculation were proposed. The results of numerical simulation and actual data processing show that the phase shift method can recover the effective high-frequency signal absorbed and attenuated by the formation to a reasonable extent while maintaining the stable numerical calculation and no distortion of the high-frequency signal. Vertical resolution of seismic data.